in an inconspicuous area just scrape it to find out if it is painted.
I highly doubt it, as it is probably molded out of a colored plastic, and if not then its done in a two part casting where the top surface is a plastic color and the backing is a more rigid plastic and diff color.
Even if it was just painted initially you would not remove it, you would just lightly key it to give it a good tooth and (primer if you prefer) paint it. I would personally take it out and do it....but just do whatever makes you more comfortable, just mask like a mad man and make sure the paint sprays back there or it will look really uneven from the outside looking in.
Carefull making it glossy though as you might get serious glare from that area, which is why its usually matt or less reflective. you can put some cling wrap down and drive around to see if you get glare, then proceed accordingly.
anywho hope some of that helps...
and no I have not seen anybody paint just that particular item on a Fit...
but ya never know....
good luck guys

post em when you got em...